The incandescent light bulb
1880
On January 27, 1880, The Patent Office granted Thomas Edison’s patent for the “electric-lamp.” His patent was an improvement on electric lamps, not the invention of them, but because of Edison’s design changes and the materials he used—such as a carbon filament—his patent allowed for an electric lamp that was reliable, safe, and practical.
National Archives, Records of the Patent and Trademark Office
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Educational Resources
- Teaching With Documents: Alexander Graham Bell's Patent for the Telephone and Thomas Edison's Patent for the Electric Lamp
- Teaching With Documents: Petition Signed by Thomas A. Edison for Sunday Openings at the World's Columbian Exposition
